Split wedge and method for making same

Abstract

A method of manufacturing a friction wedge of a rail car includes forming, in drag and cope portions of a mold, at least one cavity that defines at least some exterior features of at least one friction wedge. At least one core is inserted into the drag portion adjacent to the cavity. The core includes at least one surface configured to define a column face of the friction wedge. Rigging is formed in the drag and cope portion of the mold. The rigging includes a down sprue, at least one ingate, and at least one runner for directing molten material to the cavity. Molten material is poured into the mold to form the friction wedge casting. The friction wedge casting is removed from the mold. Rigging is removed from the friction wedge casting and the friction wedge casting is finished.

I claim: 
     
       1. A railcar truck comprising:
 a bolster having an outboard end section, the outboard end section having first and second shoe pockets; 
 a side frame including a bolster opening defined by a pair of side frame columns, a compression member, and a spring seat, the bolster opening sized to receive the outboard end section of the bolster 
 a group of springs, the group of springs positioned between the outboard end section of the bolster and the spring seat, the group of springs resiliently coupling the bolster to the side frame; 
 a first friction wedge and a second friction wedge, each friction wedge comprising:
 a column face, the column face having chamfered edges providing a smooth transition between the column face and adjacent sides of the friction wedge; 
 a sloping face; 
 a bottom side; and 
 a wear indicator on a side of the friction wedge; 
 
 a first wear plate and a second wear plate, each wear plate positioned between the respective column faces of the friction wedges and the respective side frame columns 
 a first wedge insert and a second wedge insert, each wedge insert positioned between the respective sloping faces of the friction wedges and the respective shoe pockets; 
 wherein the column face as-cast, without further finishing, of each of the friction wedges is substantially flat and has a surface finish less than 500 micro-inches RMS 
 wherein each of the friction wedges has an acicular gray iron microstructure that comprises Bainite, Martensite, Austenite, Carbide, and no more than about 5% Pearlite; and 
 wherein each of the friction wedges has a hardness of between 420-520 BHN. 
 
     
     
       2. The rail car truck of  claim 1 , wherein the chamfered edges of each of the first and second friction wedges have a radius of about 0.30 inches. 
     
     
       3. A friction wedge of a rail car comprising:
 a column face, the column face having chamfered edges providing a smooth transition between the column face and adjacent sides of the friction wedge; 
 a sloping face; 
 a bottom side; and 
 a wear indicator on a side of the friction wedge; 
 wherein the column face as-cast, without further finishing, has a surface finish less than 500 micro-inches RMS. 
 
     
     
       4. The friction wedge of  claim 3 , wherein the column face is substantially flat. 
     
     
       5. The friction wedge of  claim 4 , wherein the friction wedge has an acicular gray iron microstructure that comprises Bainite, Martensite, Austenite, Carbide, and no more than about 5% Pearlite. 
     
     
       6. The friction wedge of  claim 5 , wherein the friction wedge has a hardness of between 420-520 BHN. 
     
     
       7. The friction wedge of a rail car of  claim 6 , wherein the chamfered edges have a radius of about 0.30 inches. 
     
     
       8. The friction wedge of  claim 3 , wherein the column face has substantially flat top and bottom regions and a concave middle region, and wherein a maximum distance between a plane within which the top and bottom flat regions are disposed and an apex of the concave middle region is between 0.020 and 0.060 inches. 
     
     
       9. The friction wedge of  claim 3 , wherein the column face comprises a recessed portion. 
     
     
       10. The friction wedge of  claim 3 , wherein the column face comprises a substantially flat middle region surrounded by a groove defined in the column face. 
     
     
       11. The friction wedge of  claim 10 , wherein the groove has a depth of about 0.06 inches. 
     
     
       12. The friction wedge of  claim 11 , wherein the recessed portion includes a friction control material. 
     
     
       13. A friction wedge of a rail car comprising:
 a column face, the column face having chamfered edges providing a smooth transition between the column face and adjacent sides of the friction wedge; 
 a sloping face; 
 a bottom side; and 
 a wear indicator on a side of the friction wedge; 
 wherein the column face as-cast, without further finishing, has a surface finish less than 500 micro-inches RMS; and 
 wherein the friction wedge has an acicular gray iron microstructure that comprises Bainite, Martensite, Austenite, Carbide, and no more than about 5% Pearlite. 
 
     
     
       14. The friction wedge of  claim 13 , wherein the friction wedge has a hardness of between 420-520 BHN. 
     
     
       15. The friction wedge of  claim 14 , wherein the column face is substantially flat. 
     
     
       16. The friction wedge of a rail car of  claim 15 , wherein the chamfered edges have a radius of about 0.30 inches. 
     
     
       17. The friction wedge of  claim 13 , wherein the column face has substantially flat top and bottom regions and a concave middle region, and wherein a maximum distance between a plane within which the top and bottom flat regions are disposed and an apex of the concave middle region is between 0.020 and 0.060 inches. 
     
     
       18. The friction wedge of  claim 13 , wherein the column face comprises a recessed portion. 
     
     
       19. The friction wedge of  claim 13 , wherein the column face comprises a substantially flat middle region surrounded by a groove defined in the column face. 
     
     
       20. The friction wedge of  claim 19 , wherein the groove has a depth of about 0.06 inches. 
     
     
       21. The friction wedge of  claim 20 , wherein the recessed portion includes a friction control material.